Hydraulic transmission system



Jan. 15, 1935. R. MAW 1352781 HYD AULIC TRANSMISSION SYSTEM Original Filed March 20, 1929 4 Sheets-Sheet l IN VEN TOR.

HYDRAULIC TRANSMI S S ION SYSTEM Original Filed MarGh 20, 1929 4 Sheets-Sheet 2 III 47 a I? I 61' i mi: 7 o

IA 56' 57 M k 40 y 55 (5 INVENTOR.

ATT NEY' 'Jan. 1935- R. MAW 1,987,781

HYQRAULIC TRANSMISSION sYs'rmu Original Filed March 20, 1929 4 Sheets-Sheet 3 INVENTOR. 76M MM 4.Sheets- -Sheet INVENTOR.

Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE Original application March 20, 1929, Serial No. 351,329. Divided and this application May 31,

1930, Serial No. 457,815

18 Claims.

This invention relates to hydraulic transmission systems and particularly to variable speed hydraulic transmission systems.

This application is a division of my co-pending application Serial No. 351,329, filed March 20,

The invention has for its object generally an improved construction and arrangement of parts in devices of the character described which is emclen't, economical and readily manufactured.

More specifically an object is to provide an improved system comprising hydraulically coupled engines in which the speed and torque may be readily varied. I,

A further object is to provide a hydraulic engine oi! the rotary variety in which the mutual reaction between pistons and cylinders or other moving parts is transmitted directly to the casing without traversing the valve structure or engine parts, thereby avoiding causing stresses therein due directiy to the load.

A further object is to provide a hydraulic engine of the rotary variety with an improved valve structure whereby continuous movement of work ing fluid is accomplished in changing from cylinder to cylinder without shock and without leakage.

A further objectis to provide a hydraulic engine with improved means for varying the eccentricity of the co-acting members which produce piston displacement so that there is substantially no binding or slippage, while at the same time achieving precise adjustment.

A further object is to provide hydraulic engines and the like having rotating parts with an improved arrangement of thrust bearings 01 an anti- Iriction variety whereby they also serve as packing glands.

A still further object is to provide an improved anti-friction reciprocating device for actuating 40 with precision the eccentric members of rotary machines or mechanism required to be linearly movable to-and-fro, whereby there is relatively little lost motion and substantially very little iriction.

Other objects .of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplifled in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. l is a view mainly in vertical cross-section showing a hydraulic engine adapted to be driven as a pump in a hydraulic system constructed in 5 accordance with the invention;

Fig. 2 is a sectional view taken on the line 2-2, looking in the direction of the arrows, in Fig. 1;

Fig. 3 is a top elevational view showing the. rotating member and cooperating pistons which are employed in the engine shown in section in Fig. 2;

Fig. 4 is a view mainly in side elevation, parts being broken away, showing the valve member or bushing used in conjunction with the hydraulic engines of the present invention in order to obtain continuity in fluid movement from cylinder to cylinder;

Fig. 5 is a cross-sectional view of the valve member shown in Fig. 4 taken on the line 5-5 thereof and looking in the direction of the arrows; v

Fig. 6 is a view similar to Fig. 5 showing a crosssection of the valve member taken on the line 66 in Fig. 4;

Fig. 'I is a side elevational view of a modified form of valve bushing;

Fig. 8 is a fragmentary view partly in section and partly in elevation, showing the conduit member which connects the hydraulic engines in accordance with the present invention;

Fig. 9 is a sectional view of the conduit member taken on the line 9-9 thereof;

Figs. 10 and 11 are fragmentary sectional views showing details of the valve devices employed in the conduit member;

Fig. 12 is an enlarged view partly inelevatlon and partly in section showing a piston member of the type employed in the present invention;

Fig. 13 is a view in top elevation showing the type of piston member employed in the engines of the present invention;

Fig. 14 is a view partly in section and partly in elevation showing on a reduced scale the eccentric member and the shifting means therefor employed in connection with the engine-shown in Fig. 1;

Fig. 15 is a fragmentary view showing a detail in the construction of the movable liner associated with the eccentric member; and

Fig. 16 is a side elevation on a reduced scale showing the manner of connecting together engines of the character. illustrated in Fig. 1.. r

In hydraulic transmission systems having me chanically driven and driving engines hydraulicaliy coupled for the mutual. exchange by displacement of operating fluid in order to transmit driving force, a variation of the displacement for producing speed variations may be accomplished in either of two ways, first, by employing engines of fixed displacement and by-passing a portion of the operating fluid, and second, by employing engines in one of which the displacement may be varied. The second type is the more eflicient and it is to this type that the present invention especially relates.

In the practice of the invention, the fluid displacement is accomplished by providing cylinders having pistons that are reciprocated by the relative, rotationfijof eccentrically disposed members associated respectively with the cylinders and pistons. In devices of this character, it has been found generally preferable to vary the fluid displacement of the mechanically driven engine sinceas by this arrangement fluid slippage is reducedsubstantially to a minimum and precise regulation and high efficiencies result. In the system here illustrated, the mechanically driven engine is shown generally in Fig. 1, while the driving engine would be similar so that a single device of the present invention would have the arrangement shown in side elevation on reduced scale in Fig. 16.

The working fluid employed in accordance with the present invention may be any relatively incompressible fluid which does not readily break down and preferably has lubricating properties in addition. Water may be used but it is liable to evaporate. Other highly incompressible liquids and solutions which have good body and relatively low viscosities may also be used. Light petroleum oils, however, are preferred.

The system in general Referring now particularly to Fig. 1, 10 denotes generally the casing of the driven engine or pump which is provided with a rotating mem-. ber comprising a shaft 11 and a, rigidly attached block or cylinder member .2; the latter has a series of radially disposed bores 13, which serve as cylinders, each having a cooperating piston member 14 adapted to reciprocate therein. These pistons have their outer ends 15 disposed generally to transmit thrust and bear against an eccentric member 16 operatively associated with the casing 10. The members 12 and 16 are thus relatively eccentrically disposed, that is, have different centres in casing 10, in order that by their mutual reactions they may effect displacement of the pistons. In order, however, that the displacement of their centres may be varied, the member 16 is movably disposed in the casing 10 and to this end is formed with straight sides, shown at 17 and 17', respectively, in Figs. 2 and 14, which slide on corresponding straight slide-members 18 and 18 provided in the casing 10. The position of the member 16 on the slide-members 18 and 18 is governed by means of a reciprocating or plunger device, shown generally at 19, that has a part secured to the eccentric member and extending through the casing 10 at a convenient point, for purposes of actuation.

The casings of the driven and driving engines are rigidly connected together by the interposed auxiliary member 27 that is bolted or otherwise secured to each of the casings. 'I'hisconnecting member serves, however, not merely as a connecting means for the casings, but also as a reservoir for operating fluid and as a housing for a passage member 28. The member 28 is here shown as having a longitudinal partition 29 forming two passages therein; the member 28 having its ends respectively secured in the casings 10 and 20 and arranged to eifect communication between the cylinders in the members 12 and 22. The passages provide hydraulic connection for the driven and driving engines, through which working fluid is caused to flow by the piston displacements of the engines when running.

Driven engine or pump structure The driven engine is constructed so as to be readily assembled and disassembled; the casing 10 is accordingly shown as composed of two separable parts, denoted at 10a and 10b, respectively, secured together in any convenient manner, for example, by means of bolts, as shown at 31. The part 10:: has a central inwardly projecting boss 32 through which the shaft 11 extends.

Similarly the part 10b has a boss 33. In orderv that the casing may take up directly the entire reaction from the working of the pistons, the block or member 12 is journaled directly on the bosses 32 and 33 in any convenient manner; for example, by means of anti-friction bearings, here shown as of the ball bearing variety, interposed respectively at 34 and 35 between the bosses and the block 12. To facilitate this arrangement, the block 12 has front and rear annular grooves 36 and 37 which fit over the frames of bearings 35 and 34, thereby forming hanging ledges 38 and 39 on the block, which ledges are preferably given a slight taper, in order to lighten the block 12 about its periphery which may rotate at relatively high angular velocities. Thus tapered, the block 12 is seen to have an outside surface that has a central cylindrical portion to which conical portions are joined at either side. These conical portions may not, and preferably do not, have the same slope.

In order that the shaft 11 may be rigidly coupled to the block 12 and also conserve space, a second annular groove 40 of less diameter than the groove 36, is cut in the front of the block 12. The diameter of this groove is such that the flanged coupling head 41 formed integrally with the shaft 11 fits therein and is centered with the block. The head 41 is made fast to the block 12 by any suitable securing means, for example, by bolts, as shown at 42.

The block 12 has a central axial bore 43 of a diameter sufficient to receive a separate cylindrical member here shown as a bushing 44 which fits tightly into this bore, and has port openings 45 formed therein and disposed in register with the cylinder bores, so that this bushing serves as a valve for the cylinders. This valve bushing is bored out to have an internal diameter whereby it fits over the ported end of the passage member 28; this diameter being suflicient to give a working fit on the end of the passage member 28. The passage member 28, when properly disposed in the casing 10, has its end which protrudes into the valve bushing 44, so positioned that it serves as a hub about which the cylinder block and its valve bushing freely turn.

This protruding end portion of member 28 has two ports, one on each side of the partition 29, and denoted a7 and 47, respectively. Similar ports are, of course, provided at the other end of the member 28 here denoted 48 and 48', respectively. The ports 47 and 47' are separated by web-wall portions 49 and 50 that are disposed on opposite sides of and formed integral with the partition 29. In like manner, the ports 48 and 48' are separated by web-wall portions as 51, for example, in Figure 8. In each case these web-wall portions have an arcuate extent sufilcient to cover a port opening in the valve bushing such as shown at 44.

4 Valve structure The valve structure here employed is such that the operating fluid has continuous movement from cylinder to cylinder when the cylinder blocks in the engines rotate, it being understood that while the valve structure maybe integral with the cylinder block, for manufacturing reasons, it is preferably provided by means of a separable member, such as the valve bushing shown at 44. The bushings employed in the two engines, however, are. similar. Hence the illustration of details of but one will sufiice.

Details of the valve bushing 44 are shown in Figs. 4, 5 and 6, Fig. 5 showing on an enlarged scale the construction shown in Fig. 2 independently o1 other engine structure. Here a cylindrical body is shown provided with a plurality of elongated openings 45 longitudinally disposed with respect to the axis and distributed circumferentially about the cylindrical surface, these openings being the same in number as the cylindrical bores 13 in the block 12 with which it is to be put in register. The number of cylindrical bores in the block 12 may be, of course, any desired number; an odd number, however, is preferred, since it results in avoiding the occurrence of any positions of balanced dead centres for the cylinder block with respect to the passage member 28. A convenient number of cylindrical bores is seven. The block 12 is here shown by way ofexample as provided with seven cylinders, which are radially disposed and equally spaced about the circumference of the block. The valve bushing in the engine, therefore, has seven ports equally spaced about its operative cylindrical surface.

In order to insure continuity of fluid movement, each port opening is provided with lap ping components at the ends, the lapping component at one end of an opening being staggered with respect to the lapping component at its other end. By this arrangement it is seen that the lapping components associated with a port opening extend in opposite directions from a medial line drawn lengthwise therethrough, these companents being preierably symmetrically formed, so that there is as much area of the valve opening one one side of the medial line as on the other. The angular extent of each lapping component is such that it extends about the circumference of the valve bushing from the medial line a distance corresponding to one-half the arc subtended by a cylinder; for example, where there are seven cylinders, the arc subtended by one cylinder is and 5, the lapping components extend to the left,

in the portion of the bushing 44 next to the observer, and the components in the portion to therear extend to the right the same number of degrees. Thus, the port openings in the valve bushing, as here provided, are seen to have staggered components which span substantially completely .the arc subtended by one cylinder, so

that the cylinder communicates through some portion of a port opening during the whole time that the cylinder is rotating with the block from one position of dead centre to the opposite position of dead centre. (These positions of dead centre are seen to be when the axis of a cylinder is in line with the partition 29 of the passage member 28.) To properly operate the valves, the web-wall portions 49 and50 are designed to close the port openings in the bushing 44 whenever a cylinder is in a position of dead centre. Also it is seen that the fluid movement to or from a cylinder, as the cylinder moves into a position of dead centre, is no sooner out 01f on one side, than the opposite movement begins on the other the instant that the clyinder has passed the dead centre. As a consequence, there are no periods of complete stoppage of fluid movement and no shocks or fluid hammers occasioned by a sudden starting r stoppage in the fluid movement.

From the sections of the valve bushing shown in Figs. and 6, it is seen that there is a narrow web or partition 46 in the wall of the bushing separating the port openings 45 that has a width near a port-end which extends an arcuate distance corresponding to the lap-excess or the opposite' staggered component associated with an adjacent port opening. In Fig. 6, the middle portion of the port openings is portrayed. Here it is seen that the separating web has its greatest width,the width being that or" twice the lap-excess.

Thus it is seen that the opposite lapping components of two adjacent port openings, in the valve bushing, each extend to and are bounded by a common line drawn on the bushing surface parallel to the axis, so that a component of the second port opening begins where the first component ends. In this way, it is seen that a strong valve member is provided which not only controls the fluid movement between cylinders, but at the same time extends for a circumferential distance about the bushing which corresponds substantially with the entire arc subtended by a cylinder, so that in eifect there is provided continuous cylinder communication from cylinder to cylinder.

While the middle portion of the port openings 45 may extend mainly longitudinally, as shown in Fig. i, it is by no means essential that this portion be so disposed, as other dispositions may be equally satisfactory; for example, a diagonal disposition, anembodiment of such arrangement being shown in Fig. 7. Here the valve bushing 44' is provided with port openings 45' having a diagonally extending middle portion and separating webs 46'.

Piston structure Details of the structure of a piston, adapted to reciprocate in a cylinder bore of a cylindrical block such as is herein employed, are shown in Figs. 13 and 14. The piston is shown as having the proportions of a piston 14 and has a generally cylindrical body formed with suitable means about its lower end for preventing leakage, such for example, as a plurality of annular grooves I 55. The upper end 15 is arranged to transmit thrust with relatively little friction and'to this end is provided with a relatively deep groove 56 cut crosswise on a diametral line in which is disposed a suitable anti-friction transmitting member, for ex'a'ihple, an annular ball bearing 57 secured therein by a-pin indicated by broken lines at 58. This pin is preferably inserted through a transverse bore formed in one side the piston, there being a stop at the other side to prevent the pin from sliding endwise therethrough. The stop comprises a wall portion 59 through which is preferably bored a smaller opening 80 whereby an air pocket is avoided. A longitudinal groove or key-way 61 is also provided in one side of the piston member as a means for co-acting with a key or pin, such as shown at 62 (see Fig. 1) disposed in the wall of a cylindrical bore 13, whereby the piston may be reciprocated without rotating about its own axis. when the engine is working. The piston, as shown, also preferably has a suitable counterbore in its lower or working face, as illustrated at 63. as by this means the piston is lightened and its mechanical efficiency otherwise increased.

Eccentric member structure The eccentric member 16 is disposed in the engine in working association with the pistons 14 and reacts normally therewith to transmit thrust. In order that this reaction may take place with relatively little friction, a suitable antifriction device is preferably interposed between the eccentric member proper and the thrust members or ball bearings in the ends of the pistons, This anti-friction device is shown as of theroller bearing variety, and comprises rings 65 and 66' between which are disposed a plurality of rollers 67 heldin proper spaced relation and alignment by means of a cage 68. Fig. 15 shows details of this cage. Here it is seen that the cage 63 eornprisesa pair of annular frame members held together by means of pins 69. To accommodate this anti-friction device, the eccentric member 16 has a large groove 65 formed therein of a size suihcient for the reception of both the rings 65 and 66 and, when in place,

have a large washer 70 disposed thereagainst. A spacing ring 71 is shown additionally as interposed between the washer 70 and the casing 10 to keep the parts in place. Thus, it is seen that the anti-friction device cannot be displaced sidewise in the casing when the engine is assembled and the ball bearings 57 have rolling engagement therewith. This ring, when the engine is in working order, is thus free to travel with the rotation of the cylinder block, which it is found to do as a result of the tangential components of the thrust transmitted thereto from the pistons when rotating.

In Fig. 14, the arrangement of the eccentric member with respect to the casing 10 is illustrated independently of rotating parts of the engine. Here it is seen that the inner surface of the eccentric member 16 has the annular groove cut therein about its inner surface to a depth substantially equal to the width of rings 6566 with their interposed rollers 67 in place. The outside surface of the member is shown faced at 17 and 17 so as to slide on the slide-members l8 and 18. The outside surface of the eccentric member 16 may of course have any convenient shape, provided it affords means for effecting the sliding movement for changing the eccentricity thereof with respect to the cylinder block.

.' An octagonal form, as shown in Fig. 14, however, is convenient, since it conserves space and at the same time provides a third flat face at right angles to those at 17 and 17' to which a moving part of the plunger device 19 may be secured in order to effect the sliding movement. The octagonal sides preferably move into snug engagement with one or more fillet members 72 which are disposed about the interior of the casing 10. While the casing 10 is here shown, as

provided with integral slide-members 18 and 18', it is obvious that where convenience indicates, these sliding members can also be made separately and inserted when assembling the engine.

Thrust bearing structure The rotating member of the engine here employed while mounted so as to be free at all times to turn on the journals within the casing is preferably provided with special means in order to avoid binding and friction due to end thrusts, and to this end has thrust bearings in addition to the main bearings. Casing 10 for this purpose is shown as having the bosses 32 and 33 interiorly grooved at 73 and 74, respectively, for the reception of annular thrust bearings. One is shown as engaging with shaft 11 and block 12. It is arranged in groove 73 to fit over the shaft 11 and bear against the flange member 41, and is adapted to transmit the end thrust from the shaft directly to the casing 10. The other thrust bearing is in the groove at 7a and fits over the stationary end of the passage member 28 reacting against the end of the valve bushing 44 which is secured in block 12. Thus positioned, these thrust bearings are adapted to perform a secondary function and tend to prevent oil leakage In any substantial quantity past the same. It is preferred, however," to insure more positively against the possibility of oil leakage past the thrust bearing at 73 to the outside of the casing, by providing additional means, for example, an ordinary packing gland. Such gland is here shown and comprises a packing ring hearing against packing material inserted at 76. This packing ring is drawn into place by means of nuts and bolts shown at 77 in the conventional manner.

Connecting means structure The connecting means, as indicated above, comprises the cylindrical member 27, which serves as a link securing together the casings 10 and 20, and the passage member 28 which provides hydraulic passages for connecting the cylinders in the two engines. This passage member is seen to be a generally cylindrical body comprising a cylindrical wall and end portions and is divided by the longitudinally disposed partition 29 forming two passages therein, one serving as the inlet passage to the pump when the order of increasing piston displacement takeaplace in one direction, while the other at the same time serves as the outlet passage. When the order of increasing piston displacements is reversed, then the flow of working fluid in the passage member 28 is also reversed. This passage memher, as shown in Fig. 1 is secured against rotation in the bosses on opposing walls of the engine casing. To this end, it is shown as making a tight fit in the bosses as 33. The passage member 28 is first inserted in the casing 10 when it is so positioned that the longitudinal partition 29 lies in a plane substantially parallel with the ways 18 and 18' of the casing 10.

To form ports in the end portions of the cylindrical wall of the member 28, the wall is cut out crosswise on each side symmetrically with respect to the partition 29. As shown in Fig. 8, such cut away portions are made equally on the upper and lower sides to form ports 47 and 47. The ports 48 and 48' are similarly formed at the other end. These four ports are seen to have substantially rectangular developments, and are separated by the web-walls 49, 50 and 51 which have straight 1,987,781 tit edges and serve as valve cut-offs and are preferably so disposed with respect to the partition 29, that substantially one-half of each web-wall projects away-from the partition, as shown in Fig. 2. The arcuate extent of these web-walls, as noted above, is such as to cover substantially completely one cylinder port in the valve bushing 44, which for a seven-cylindered-engine has an angular extent of one-seventh of a circumference. By thus cutting away the cylindrical wall of member 28, end portions 53 and 54 remain forming disc-like end-walls which are spaced slightly from the heads on-shafts 11' and 21 when the passage memhex-'28 is in place.

As the working fluid is relatively incompressible, it is seen that the total displacement of the 'pistons in the casing 20 must at all times correspond substantially to the total displacement of the pistons 14 in casing 10. In order, however, to allow for transient variations and to compensate for a certain amount of expansion and contraction in the volume of working fluid operatively employed in the engines, it is desirable to provide the passage mcmber 28 with automatic means in the nature of volume regulators or safety valves as shown at 80 in Figs. 1 and 9. Such safety valve is shown in enlarged view in Fig. 10, where it is seen to comprise a hollow plug member 81 adapted to be screwed into the cylindrical wall of the passage member 28 opposite the partition 29 and has communication with one of the passages therein; this member 81 having a valve seat at 82 on which seats a valve 83 that is yieldably held in place by "means of a spring 84. This spring is preferably adjustable so that the valve may be unseated at various desired pressures and for this purpose is shown as having an adjusting screw 85.

The workin'gfluid that escapes from these safety valves 80 discharges into the connecting member 27 which is arranged to serve as. a reservoir for such fluid as is retained outside of the operating channels of. the engines and the connecting passage member.

In order that working fluid may be automatically taken into the system to fill the same and to dislodge and replace air that is expelled through valves 80, the passage member 28 is also provided with additional means here shown as automatic inlet valves 86 disposed to communicate respectively with the passages in the passage member 28. Dctails of these latter valves are shown in Fig. 11. Here the automatic inlet valve comprises a hollow body member which has an outlet valve seat 87 on which seats a valve member 88 held in place under the influence of an interiorly disposed spring 89. Thus, it is seen that when the fluid inside the system contracts or an excessive negative pressure develops, fluid from the reservoir is drawn into the circulating system. For filling purposes, the passage member 28 has a plug 90 communicating with one of its passages which may be opened when the system is to be charged with fluid. In order to afford ready access to the plug 90, the connecting member 2'7 has a removable cover plate 91 disposed over the plug.

The connecting member when serving as a reservoir is preferably filled with working fluid to a height which is slightly above the inlet plug 90 and the valves 86, since such liquid level keeps the system automatically properly filled.

The connecting member is also shown as pro-- vided with a drain at 92, in order that excess or used working fluid may be withdrawn, when de.- sired. The position of the drain, however, is optional, it being understood that drains may be provided throughout the system where convenience dictates.

The operation to the mechanism to which driving force is to be transmitted. When starting the prime mover, the reciprocating device 19 is preferably first moved, so that the eccentric member 16 occupies its neutral position. The prime mover will then cause the rotating member 12 to rotate without causing any displacement of the pistons 14, the pistons under these conditions all occupying positions in their respective cylinders which are midway between the innermost and outermost positions.

When the rotating member starts rotating, it is seen that centrifugal force operates to cause all the pistons 14 to bear against the movable ring 66 of the anti-friction device. The ball bearings 57 consequently contact with and track upon the ring 66 causing it to react and travel with a speed approaching that of the rotating member 12.

If the plunger mechanism 19 be actuated to move theeccentric member 16 from the neutral or concentric position to an eccentric position,

for example, that shown in full lines in Fig. 2, then the member 16 will act to cause displacement of the pistons 14.

Assuming that the prime mover is causing the rotating member 12 to execute motion of rotating in a counter-clockwise direction, it is seen from Fig. 2 that when a piston passes through the dead centre on the right (that is. rotates through the position when the axis is in a horizontal line drawn to the right through the partition 29) it begins to move outwardly, this outward movement beginning at the same instant that the upwardly extending lapping-component of its port opening 45 passes theupper edge of the wall web 49. Consequently, this outward movement of a piston 14, as soon as it leaves the dead centre on the right, produces a drawing in or suction of working fluid from the upper passage in member 28, which suction continues during the entire time the piston moves through the upper half of its arc of travel, i. e. until it reaches a second position of dead centre, which is at the left of partition 29. As the piston approaches this latter position, it is seen to bemoving into its outermost position when its cylinder will contain the maximum amount of working fluid. During the instant that the cylinder passes through this second dead centre its port opening is again completely closed, this time by the web-wall 50. During the instant that the port opening is closed, no working fluid flows into or out of the cylinder. As soon, however, as a cylinder has passed this second dead centre, the piston will start to traverse the lower half of its arc of travel and is caused to move inwardly as a result of the reaction from engagement through member 57 with the ring 66 in eccentric member 16. It is also seen that "sure to flow through the'lower passage in the member 28 from the pump into the cylinders of the member in casing 20; this direction of flow continuing as long as the eccentric member 16 is in the position on the left shown in Fig. 2.

For such position of the eccentric member, it is seen that there is a positive pressure in the fluid on the lower side of the partition 29 in the passage member and a negative pressure or suction in the passage on the upper side. Working fluid is thus pumped by the driven engine into the driving engine through the member 28 where the pressure operates against the working faces of substantially one-half of the pistons in the driving engine; these pistons being those in the lower half of the arc of travel when the lower passage in member 28 contains working fluid under positive pressure. This pressure causes these pistons to move in a direction whereby the operating fluid can flow to a state of lower pressure. This is seen to be when the pistons move outwardly and cause a rotation of the driving engine rotating member in a. clockwise direction.

During this period working fluid flows into the cylinder of such piston and exerts pressure against its working face causing it to react and produce rotation in a clockwise direction until it reaches a position of dead centre on the left. When in this latter position the cylinder contains a maximum amount of working fluid, and is cut oil for an instant from communication with either of the passages in the member 28. As soon as such piston has passed through the position of dead centre on the left, it begins to traverse the upper half of the are of travel and permits a discharge of working fluid into the upper passage inthe passage member through a lapping component of its port opening which establishes communication with the upper passage in member 28 past the web-wall 52. This discharge continues until such cylinder is completely discharged and its piston again moves to its innermost position which occurs at the instant that it reaches the dead centre position on the right.

The pressures in the passages of member 28 are substantially equal and opposite in magnitude where there is no fluid leakage, consequently, the effective pressure differential of the present hydraulic system is approximately the sum of these magnitudes. This sum, however, is not a constant, but varies with the load, since its pressure components are reactively transmitted through the working fluid between the engine, this sum being proportional to the load resistance to be overcome.

The rate at which the rotating member of the driving engine revolves is variable in the present system, since it is seen that this rate is directly dependent upon the volume of fluid displaced in the system, this displacement being dependent upon the eccentricity of the member 16 in the driven engine. When the eccentric member 16 is in neutral or position of zero eccentricity, the pistons 14 revolve without executing any reciprocating motion, so that no working fluid is displaced, consequently, there is no flow through the driving engine,.and its rotating member remains stationary.

Assuming now that the eccentric member 16 is moved slightly from the neutral position toward the left hand position of eccentricity shown in Fig. 2, such eccentric position will cause a piston 14 to be displaced in the cylinder bores 13 an axial distance corresponding to the distance between the centres of members 12 and 16. This will produce a displacement of a small amount of working fluid and cause a flow from the driven engine to the driving engine, which in turn will move the pistons in the rotating member of the driving engine at a rate which accommodates this displacement. Since the eccentricity of the eccentric member of the driving engine with respect to the rotating member therein is fixed, the pistons of the driving engine will always execute their maximum displacement. Hence they produce but slow rotation of rotating member when accommodating the slight fluid displacement caused by the rotating pistons 14 Just described. By increasing the eccentricity of the member 16, the speed with which the rotating member of the driving engine rotates is increased until the position of maximum eccentricity for the member 16 is reached on the left. At this timethe rotating member of the driving engine attains its maximum clockwise rate of rotation.

Assuming again that the eccentric member 16 is moved from its neutral position to a position slightly on the right, it is then seen that a piston 14 passing through a position of dead centre on the left begins to move outwardly as the piston traverses the lower half of the arc of travel in a counter-clockwise direction. From this it is seen'that the lower passage in the member 28 has a negative pressure, whereas the upper pas sage has now a positive pressure. This reversal of the conditions of pressure in the passages in member 28 reverses the application of pressure on the working faces of the driving engine pistons, so that these pistons tend to move in a reverse direction to reach a state of lower pressure, that is, they move in a counter-clockwise direction. For a position of slight eccentricity in the member 16 on the right of neutral, the rotating member of the driving engine is caused to rotate but slowly in a counter-clockwise direction. This rate of rotation is increased upon increasing the eccentricity of the member 16 by moving it toward the right until a position of maximum eccentricity on the right is reached. At this time the rotating member of the driving engine is caused to rotate with a maximum angular velocity in counter-clockwise direction. By thus varying the eccentricity of the member 16 in the driven engine, the driving engine can be made to run at any desired speed in either direction. It is seen also that the torque in such case depends upon the load which reactively determines the pressure that is transmitted through the working fluid between engines. Such pressure when acting on the faces of the pistons 14 reactively determines the force of load resistance to be overcome by the driven engine and the prime mover that is coupled to it. The torque and the angular velocity of the driving engine determine the power being delivered at any instant by the present system.

When the present system is working, it is seen that only the working fluid, which is being forced through the passages in the member 28 by the pistons of the engines, is under positive pressure. While there may be working fluid in the engines that has passed the pistons, it is seen that this fluid is under substantially no pressure, consequently, there is substantially no tendency for working fluid to leak through joints of the casings.

The absence of high pressure in the system of the presentinvention in parts other than the working channels, avoids the necessity for providing large and strong stufling boxes about the shafts in the two engines. The absence of such stufilng boxes not only conserves space and lightens the engines, but it reduces the energy otherwise required to be spent by the prime mover in overcoming friction in the transmission system.

Also it is seen that since centrifugal force holds the pistons in the rotating members of the engines against the inner rings of the anti-friction devices in both engine casings, there are tangential components of thrust causing these rings to travel with the rotating members which are transmitted thereto by the pistons. It is seen further that since the inner rings, on which the ball bearings in the ends of pistons track, are eccentric with respect to the rotating members, these ball bearings travel on these rings as though they were alternately descending and ascending an inclined plane. It is thus advantageous for each piston to have its 'own independent anti-friction means in operative association with the eccentric member; this involves disposing ball bearings such as shown at 57 so as to bear on movable rings 66 whereby they may each execute an oscillating motion in one direction when descending the in-- clined plane on the rings 66, the direction of oscillation being reversed when the ascent of the inclined plane is being accomplished. This oscillation will be seen to be at different rates for difl'erent positions of the pistons since the inclined planes here have curvature. The transmission of thrust from the pistons to the ultimate eccentric members through the twofold anti-friction means of the present invention is thus seen to reduce the friction of transmission to substantially a minimum.

From the operation of the engines thus described, it is seen that in the e ent the space occupied by working fluid in the passages of member 28 and in the cylinder chambers is not entirely filled with the proper amount of fluid when the prime mover is started, then as soon as the prime mover is started centrifugal force immediately operates to cause the pistons 14 to move outwardly to their fullest extent against the inner ring 66, thereby causing them to draw in one of the valves 86 and suck in a sufficient amount of working fluid to cure this deficiency. In like manner, should any heating of the working fluid take place when the system is running so that the working fluid expands, then one of the valves 80 will open to allow exit of a suflicient amount of working fluid into the casing 27, to compensate for this expansion in the operating channels. The working fluid in the casing 27 may, of course, be renewed, drawn off and replenished as conditions may indicate.

Where the working fluid is oil, this working fluid may be relied upon as the sole lubricating agent. Any suitable system of circulating lubricant to the working parts of the transmission system of the present invention may be adopted. In such case, the reserve oil in the casing 27 may be used to provide a head of oil for circulating the lubricant; suitable passages to the engines from the reservoir being provided through the engine casings for this purpose.

When starting the transmission system, it is desirable to have the eccentric member 16 in neutral as indicated above, since then the prime mover can be started independently of the load,

" the load being thrown upon the prime mover, and

the mechanism to be driven brought up to a desired speed, by moving the eccentric member from neutral to one of its positions of eccentricity. The mechanism being driven may also be stopped by moving the eccentric member back to neutral. If tgge ccentric member be moyed through neutral to" a position of opposite eccentricity, it is seen that a braking effect is at once produced which efiects a more or less sudden stopping of the mechanism being driven. The system of the present invention is thus adapted to produce braking efiects, as well as driving effects, and accomplishes the complete control and transmission of power independently of any auxiliary devices, such as clutches couplings and brakes.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It will be understood, for example, that the bushing member 44, which injts preferred form shown in the drawings is cylindrical, might be made in the form of a irustrum of a cone or other form, as will be apparent to those skilled in the art. It will also be obvious that the form of the port openings may be varied from' that shown to accomplish the purpose of the invention, that is, to obtain a considerably greater initial flow, as for example by the use of lapping components in the form of semi-circle, in cross section, or in the form of a trapezoid or other regular or irregular shape which would give a suflicient lap opening to increase the initial flow between the cylinders and the corresponding passageway. It is to be understood, therefore, that the term lapping component as employed in the claims is intended to cover a portion of less maximum width than that of the main body,

said portion extending circumferentially outwardly from a main port area, and includes not only the form shown in applicant's drawings but also the various obviously equivalent forms. Obviously, what is meant by a main port area is what appears in applic'ants drawings (Fig. 4) as a rectangular section, although other regular geometric forms as a circular area, an elliptical area and other simple forms are intended to be included within the scope of this term.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a hydraulic engine, the combination with a casing consisting of two separable parts, each provided with an opening having an inwardlyprojecting boss, said openings being oppositely disposed in the assembled casing, of a rotatable member having radially-disposed cylinders, said member having recesses in its two faces, antifriction bearings disposed in said recesses and supported on said bosses, a second recess in one face of said member, a shaft disposed in said second recess coupled to said member and projecting through the adjacent boss, means secured in the other boss for accommodating the passage of working fluid to and from said cylinders, a valve mechanism interposed between said secured means and said rotatable member having ports leading from the said secured means to the said cylinders, each of said ports having a main port area of regular form and a lapping component of less maximum width than that of the main port area to provide an advance initial port opening between the cylinders and the corresponding passageway in said secured means, pistons in said cylinders having thrust mechanisms operatively disposed on their outer ends, and an annular element associated with said casing about said member and adapted to receive the thrust from said pistons.

2. In a hydraulic engine, the combination with a casing consisting of two separable parts, each provided with an opening having an inwardly projecting boss, said openings being oppositely disposed in the assembled casing, of a rotatable member having radially-disposed cylinders, said member having recesses in its two faces, antifriction bearings disposed in said recesses and supported on said bosses, a second recess in one face of said member, a shaft disposed in said second recess coupled to said member and projecting through the adjacent boss, said member having a central bore in the face opposite said second recess, a hub secured in the other boss and projecting centrally into said bore and provided with passages adapted to afford ingress and egress of working fluid for said cylinders, a valve mechanism interposed between said hub and said rotatable member having ports leading from said hub to said cylinders, each of said ports having a main port area of regular form and a lapping component of less maximum width than that of the main port area to provide an advance initial port opening .between the cylinders and the corresponding passage in said hub, pistons in said "cylinders having anti-friction thrust mechanisms operatively disposed on their outer ends, antifr'iction'" thrust bearings disposed respectively about said shaft and said hub between said bosses and said rotating member, and an annular element having eccentric disposition with respect to said member associated with said casing adapted to receive the thrust from said pistons.

3. In a valve mechanism for use in rotary hydraulic engines, a bushing member comprising ferentially lapping components staggered axially V a solid of revolution having a plurality of ports elongated axially and equally spaced about the circumference, each of said ports having circumand positioned to form a regular-series of communications about the periphery effecting arcuate continuity for fluid movement therethrough.

4. In a valve mechanism for use in rotary hydraulic engines, a bushing member'comprising a solid of revolution having a plurality of ports elongated axially and equally spaced about the circumference, each of said ports having a circumferential lapping component at each end which extend oppositely from a medial line drawn parallel to the axis through the port, the total arcuate extentzof said-components for each port being equal. to'the arc subtended by a cylinder of the engine.

5. In a valve mechanism for use in rotary hydraulic engines, a bushing member comprising a cylindrical body having a plurality of ports elongated axially and equally spaced about the circumference, each of said ports having a cirimferential lapping component at each end extend oppositely from a medial line drawn parallel to the axis through the port, the line drawn parallel to the axis and through the surace of the component at one end of any port lying also in the side of an opposite component of an adjacent port.

6. In a hydraulic engine, the combination with a casing having openings at opposite ends provided with bosses, of rotatable means formed with radially-disposed cylinders and iournalled "ronsaid bosses, pistons on said cylinders having "king secured in said means about said hub and thrust members projected outwardly therefrom, a ported hub having valve walls, secured in one of said openings, disposed centrallybf-said rotatable means, adapted to communicate with the cylinders therein and provided with passages for accommodating the ingress and egress of working fluid, a valve mechanism associated with each of said cylinders and having ports arranged to span a valve wall, each of said ports having a main port area of regular form and a lapping rectangular component of less maximum width than that of said main area to provide an advance initial port opening and an annular element having relatively movable portions and disposed in said casing about said -means in contact with and adapted to receive the thrust from said pistons.

7. In a hydraulic engine, the combination with a casing having openings at opposite ends provided with bosses, of rotatable means formed with radially-disposed cylinders and journalled on said bosses, pistons in said cylinders having thrust members projected outwardly therefrom, a ported hub having valve walls, secured in'one'of said openings, disposed. centrally of said rotatable means, adapted to communicate with the cylinders therein and provided with passages for accommodating the ingress and; egress of working fluid, valve mechanism associated with each of said cylinders and having apertures each of which includes a main port area of regular form and forwardly and rearwardly extending lapping components of rectangular form having a less width than the maximum width of said main area for initiating the flow to and from the cylinders and the corresponding passage in the said hub, said apertures being arranged to span a valve wall, and an annular element having relatively movable portions and disposed in said casing about said means in contact with and adapted to receive the thrust from said pistons, the only outward force acting on said pistons arising centrifugally or from fluid pressure in said cylinders.

8. In a hydraulic engine, the combination with a casing having openings at opposite ends provided with bosses, of rotatable means formed with radially-disposed cylinders journalled on said bosses, pistons in said cylinders having thrust members projecting outwardly therefrom, a

ported hub having valve walls, securedin one of said openings, disposed with respect to said means and provided with passages adapted to communicate with said cylinders, removable valve mechanism having apertures interposed between said hub and said means, whereby fluid communication between said hub and said means is controlled when the latter is rotating, said apertures having a main port area of regular form and forwardly and rearwardly extending lapping components having a maximum width less than that of said main area for initiating the flow between said cylinders and said ported hub and an annular element having relatively movable por-' having ports adapted to control communication between said hub and said means when the latter is rotating, said ports having a main port area of regular form and a lapping component having a maximum width less than that of said main area and a forward boundary parallel to the axis of rotation, said component extending circumferentially a substantial distance in advance of said main port area, and an annular element having relatively movable portions and disposed in said casing about said means and in contact with and adapted to receive the thrust from said pistons.

10. In a hydraulic engine, the combination with a casing having openings at opposite ends progagement with the projecting end 01' said hub,v

provided with ports and disposed to be in registry with the cylinders in said means, said ports having lapping components extending oppositely from a medial line drawn through the port parallel to the axis of said bushing and subtending a total arcuate distance substantially equal to that subtended by one cylinder, and an annular element having relatively movable portions disposed in said casing about said means and in contact with and adapted to receive thrust from said pistons.

11. In a hydraulic engine, the combination with a casing, of rotatable means journalled in said casing, a plurality of cylinders associated with said means, cooperating pistons in said cylinders arranged to reciprocate therein, an annular element disposed eccentrically within said casing with which said pistons react, a ported passage member having arcuate valve walls on opposite sides and supply and discharge conduits communicating with said cylinders, a valve mechanism in said means arranged to control communication between said cylinders and said member, said mechanism having ports the arcuate extent of which spans a valve wall for effecting a continuous communication between said cyl inders and said member, each of said ports having one component circumierentially extending from said port and having a second component circumterentially extending from said porn/staggered axially with respect to the said one component.

12. In a hydraulic engine, the combination with a casing, of rotatable means journalled in said casing, a plurality of cylinders associated with said means, cooperating pistons in said cylinders arranged to reciprocate therein, an annular element disposed eccentrically within said casing with which said pistons react, a ported passage mechanism having arcuate valve walls on opposite sides, and supply and discharge conduits communicating with said cylinders, and a valve including a member disposed in said means about said mechanism having ported openings provided with staggered portions disposed to have an aggregate arcuate extent on opposite sides of the main portion of a port opening such as to subtend" a total are spanning a valve wall and substantially equal to that subtended by one cylinder.

13. In a hydraulic engine, the combination with a casing, of rotatable means journalled in said casing, a plurality of cylinders associated with said means, cooperating pistons in said cylinders and arranged to reciprocate therein, an annular element disposed eccentrically within said casing and with which said pistons react, a ported passage member having arcuate valve walls onopposite sides and supply and discharge conduits disposed to connect with said cylinders, a valve mechanism including a removable bushing secured in said means and provided with port openings in registry with said cylinders, said openings having lapping components at each end extending in opposite directions from a medial line drawn through the port parallel to the axis of said bushing and having a total arcuate extent spanning a valve wall and substantially equal to that subtended by one cylinder.

14. In a hydraulic engine, the combination with a casing, of rotatable means journalled in said casing, a plurality of cylinders associated with said means, cooperating pistons in said cylinders arranged to reciprocate therein and hav ing anti-friction thrust units in their ends, an annular element disposed eccentrically with said casing with which said units react, a passage member having supply and discharge conduits disposed to connect withsaid cylinders, valve mechanism disposed in said means about said member for controlling communication between said cylinders and said member, said-mechanism including a device having ports in registry with said cylinders, each of said ports having a forwardly extending portion and a rearwarly extending portion, the forwardly extending portion of each port being in axial alignment with the rearwardly extending portion or the preceding port, to cause continuity of flow of a large percentage of the fluid in said system, and a pair of rings having anti-friction means interposed therebetween mounted in said element and having a part associated with said pistons and a part associated with said element.

15. In a hydraulic engine, the combination with a casing, of rotatable means journalled in said casing, a plurality of cylinders associated with said means, cooperating pistons in said cylinders arranged to reciprocate therein, an annular element associated with said casing comprising a stationary ring and a movable ring carried by said stationary ring adapted to travel with said means, anti-friction thrust units on the ends of each of said pistons and disposed to bear against said movable ring, a passage device having conduits for accommodating the ingress and egress of working fluid, and a ported end with valve walls spanning an are equal to that subtended by a cylinder and secured in said casing, a valve mechanism including a member secured in said means about said ported end, having port openings provided with circumferential components staggered axially to provide substantially continuous communication between said device and said cylinders, and anti-friction reciprocating means changing the relative position of said annular element in said casing.

16. In a device of the character described, the combination comprising a casing, rotatable means journaled in said casing, a plurality of cylinders associated with said rotatable means, pistons in the said cylinders, a passage member having supply and discharge conduits adapted for communicating with said cylinders, and a valve mechanism associated with said rotatable means interposed between said passage member and said rotatable means, said valve mechanism having openings adapted to lead from said cylinders to said passage member during operation of the device, said openings having a main port area of regular form and lapping components having a maximum width less that of said main area for initiating the flow between the cylinders and said passage member.

17. In a valve mechanism for use in rotary engines, a member: comprising a sleeve having 5 a plurality of ports elongated axially and equally spaced about the circumference, each of said ports having circumferential lapping components staggered axially and positioned to i'orm a regular series of communications about the 10 periphery eifecting arcuate continuity for fluid movement therefrom.

18. In a device 01' the character described, the

combination comprising a casing, rotatable means journaled in said casing, a plurality of cylinders associated with said rotatable means, pistons in the said cylinders, a passage member having supply and discharge conduits adapted for communicating with said cylinders, and a valve mechanism associated with said rotatable means interposed between said passage member and said rotatable means, said valve mechanism having ports adapted to lead from said cylinders to said passage member during operation of the device, each of said ports having a forwardly extending portion on one port substantially in axial alignment with a rearwardly extending portion on the preceding port to provide continuity of flow in the device.

ROBERT MAW 

